Using Promise and await instead of then()

Question

I'm using MusicKit-JS and while this code works I don't know if there's another way of writing it.

The music methods themselves all return __awaiter(...).

Is there a way to write this using promises? I don't know much about them so couldn't get it working using promises.

music.stop()
    .then(function () {
        music.setQueue({})
            .then(function () {
                music.setQueue({ song: id })
                    .then(function () {
                        music.play()
                    })
            })
    });

[Aren't promises just callbacks?](https://stackoverflow.com/q/22539815) — VLAZ, Aug 15 '21 at 17:35
Check the last code block in this answer for a way with await: https://stackoverflow.com/a/39458285/572644 — Daniel Hilgarth, Aug 15 '21 at 17:39
It's not clear from your question: Is the code you've shown working and you just don't like the nesting? Or is the code you've shown *not* working? Separately: What's `__awaiter(...)`? The documentation should tell you. — T.J. Crowder, Aug 15 '21 at 17:40
@T.J.Crowder Afaik, `__awaiter` is part of transpiled code, the classic coroutine runner to be used with promise-yielding generator functions, and probably won't be documented anywhere. — Bergi, Aug 15 '21 at 17:52

jfriend00 · Accepted Answer · 2021-08-15T17:45:13.220

2

Assuming these functions are all returning promises, you can wrap it in an async function and then use await and then get rid of the deep nesting:

async function run() {
    await music.stop();
    await music.setQueue({});
    await music.setQueue({song: id});
    await music.play();
}

run().then(() => {
    console.log("done");
}).catch(err => {
    console.log(err);
});

edited Aug 15 '21 at 17:45

answered Aug 15 '21 at 17:40

jfriend00

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score 0 · Answer 2 · answered Aug 15 '21 at 17:40

0

All you need to do is declare your functions async. Then you will be able to use await

async function() {
await music.stop();
//    .then(function () {
await        music.setQueue({})
//            .then(function () {
await                music.setQueue({ song: id })
//                    .then(function () {
                        music.play()
                    })
            })
    });

answered Aug 15 '21 at 17:40

ControlAltDel

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What do you mean by "*declare your functions async*"? Why the plural? There's only one function in your code snippet. – Bergi Aug 15 '21 at 17:50

Using Promise and await instead of then()

2 Answers2